Problem: $ { \left[\begin{array}{rr}{2} & {0} \\ {4} & {1} \\ {4} & {-1}\end{array}\right]-\left[\begin{array}{rr}{4} & {1} \\ {-2} & {-1} \\ {-2} & {-2}\end{array}\right] = {?} } $
Explanation: To find the difference of two matrices, subtract the corresponding items between each matrix. ${\left[\begin{array}{rr}{2}-{4} & {0}-{1} \\ {4}-{-2} & {1}-{-1} \\ {4}-{-2} & {-1}-{-2}\end{array}\right]}$ Now, simplify: ${\left[\begin{array}{rr}{-2} & {-1} \\ {6} & {2} \\ {6} & {1}\end{array}\right]}$